Cells have been long known to be cultured in containers specially designed for cell culture.
In prior art, a predetermined number of cells to be cultured is suspended in liquid solutions, which are later introduced into special containers in which cell proliferation occurs, in particular environmental conditions prepared for is this purpose, with cells possibly adhering to a special support.
The environmental conditions for culture may require cells to be supplied with oxygen and heated to a predetermined temperature.
For this reason, the cells to be cultured are introduced into containers that are later placed into an incubator whose environment is maintained in sterile conditions and with controlled temperature and gas composition.
Cell culture may essentially be carried out with two types of methods, i.e. a static method and a dynamic method.
In short, according to the static method, a cell-containing solution is placed in a culture container and is left lying therein with a second culture solution until cells proliferate to predetermined amounts, whereas, according to the dynamic method a solution that contains cells to be cultured is introduced into the culture container in which a second culture solution is later circulated between an inlet and an outlet thereof, and in which appropriate support structures hold the cells in the container while causing the per fused culture solution to flow out.
This solution may be re-circulated by a special circuit of pipes or is designed to be lost.
The support structures are used when the solution flows require cell binding elements, i.e. elements whose morphological structure or physic—chemical features promote cell binding.
When the cell culture provides the required amounts of cells, both on the surfaces of containers and on those of the binding elements, cells are recovered using a chemical or biological agent which is later removed by washing and by a mechanical scraping action in combination with washing.
The above described prior art suffers from certain drawbacks.
A first drawback is that the cell culture is exposed to pollution by environmental agents during handling, because containers are often open or designed to be closed by plugs, but have no device for preserving sterility where cell culture occurs.
Another drawback is that, before transporting or administering the cultured cells to a patient, these are required to be transferred into a suitable container, which should affect as little as possible their function until administration or use.
However, the sterile chain is broken during such transfer, as the containers in which the cells are transported are opened several times.
A further drawback is that the prior art containers are alternately constructed and designed for either static or dynamic culture and cannot be used for both.
Another drawback is that the prior art containers cannot easily exchange gases, particularly oxygen, with the cells, especially when these are placed in areas of the containers that are far from oxygen inlet points.
A further drawback is that, when using cell binding elements, these must be held fully immersed in the solution in which the cells are suspended, but without allowing the level of such solution to be too high above such elements, because the solution acts as a barrier for the passage of oxygen (or other gases) to the cells, and the higher the level in the container, the harder is gas exchange with the cells.
It shall be noted in this respect that, during their life cycle, cells generally is absorb oxygen and emit carbon dioxide to be evacuated from the containers to prevent saturation.
A further drawback of dynamic culture is that continuous passage of solution flows may generate turbulence in the container, and thus hinder cell proliferation.
Yet another drawback is that the step of detachment of cultured cells from their culture surfaces causes damages to part of the detached cells, and reduces culture effectiveness.
A further drawback is that limited culture spaces are available in prior art devices.
Another drawback is that a considerable part of the internal volume of culture devices has to be left empty for free gas circulation.
Another drawback is that some culture containers require special treatments of culture surfaces to promote bonding of the cells to be cultured.